Hi,
As far as i know there is no way to cancel a post. Your only option is to
rely on the moderators to not let your post through.
But i don't see a reason to not allow a post if it is on topic. Btw i am
one of the moderators for this list. And if you were to send a mail to the
moderators, then this second mail woul appear later than the 'wrong' one
and your first mail would be allowed anyways.
Sigrid